Changes between Version 24 and Version 25 of Notes/ExampleReduction

Timestamp:

04/01/09 11:32:26 (15 years ago)

Author:

JamieStevens

Comment:

--

Notes/ExampleReduction

@@ -351 +351 @@
 central frequency, we will control dac_repeat.pl with a parameter file.
 
+We first need to calculate the primary beam size of the antenna for each central frequency, which is simply
+
+1.22 * (c/f) / D
+
+where c is the speed of light, f is the central frequency and D is the diameter of the telescope, in this case 22m.
+Using this information, and the beam sizes that were computed during the restor operations above, we can determine
+the image sizes (in pixels) that we need to image 3 times the primary beam size. All this information is in the
+table below.
+
+|| Centre Freq (MHz) || Primary Beam (arcmin) || Synthesised beam (arcsec) || Image size (pixels) ||
+||  4540             ||  12.589               ||  26.672 x 22.525          ||  255 x 302          ||
+||  4668             ||  12.243               ||  25.265 x 21.494          ||  262 x 308          ||
+||  4796             ||  11.917               ||  24.635 x 20.907          ||  261 x 308          ||
+||  4924             ||  11.607               ||  23.992 x 20.378          ||  261 x 308          ||
+||  5052             ||  11.313               ||  23.463 x 19.901          ||  260 x 307          ||
+||  5180             ||  11.033               ||  22.910 x 19.483          ||  260 x 306          ||
+||  5308             ||  10.767               ||  22.394 x 19.020          ||  260 x 306          ||
+||  5436             ||  10.514               ||  21.931 x 18.553          ||  259 x 306          ||
+||  5564             ||  10.272               ||  21.531 x 18.208          ||  258 x 305          ||
+||  5692             ||  10.041               ||  21.018 x 17.827          ||  258 x 304          ||
+||  5820             ||  9.820                ||  20.568 x 17.428          ||  258 x 304          ||
+||  5948             ||  9.609                ||  20.152 x 17.082          ||  257 x 304          ||
+||  6076             ||  9.406                ||  19.800 x 16.781          ||  257 x 303          ||
+||  6204             ||  9.212                ||  19.379 x 16.469          ||  257 x 302          ||
+||  6332             ||  9.026                ||  19.053 x 16.110          ||  256 x 303          ||
+||  6460             ||  8.847                ||  19.330 x 16.151          ||  247 x 296          ||
+
+So we make a file called dac_invert_args.txt that looks like this:
+
+{{{
+4540 cell=26.672,22.525 imsize=255,302
+4668 cell=25.265,21.494 imsize=262,308
+4796 cell=24.635,20.907 imsize=261,308
+4924 cell=23.992,20.378 imsize=261,308
+5052 cell=23.463,19.901 imsize=260,307
+5180 cell=22.910,19.483 imsize=260,306
+5308 cell=22.394,19.020 imsize=260,306
+5436 cell=21.931,18.553 imsize=259,306
+5564 cell=21.531,18.208 imsize=258,305
+5692 cell=21.018,17.827 imsize=258,304
+5820 cell=20.568,17.428 imsize=258,304
+5948 cell=20.152,17.082 imsize=257,304
+6076 cell=19.800,16.781 imsize=257,303
+6204 cell=19.379,16.469 imsize=257,302
+6332 cell=19.053,16.110 imsize=256,303
+6460 cell=19.330,16.151 imsize=247,296
+}}}
+
+And we run invert using dac_repeat.pl like this:
+
+dac_repeat.pl --task invert --repeat vis --repeat-freq rnovalmc --repeat map --repeat-freq rnovalmc_m2_%f.map --repeat beam --repeat-freq rnovalmc_m2_%f.beam "select=-auto,-ant(6)" stokes=ii options=mfs,sdb slop=1 --args-file dac_invert_args.txt
+
+This makes the triple-sized maps and beams, and now we have to chop out the normal sized map
+using imframe. We make the file dac_imframe_args.txt that looks like this:
+
+{{{
+4540 region=relcenter,boxes(-42,-50,42,50)
+4668 region=relcenter,boxes(-43,-51,43,51)
+4796 region=relcenter,boxes(-43,-51,43,51)
+4924 region=relcenter,boxes(-43,-51,43,51)
+5052 region=relcenter,boxes(-43,-51,43,51)
+5180 region=relcenter,boxes(-43,-51,43,51)
+5308 region=relcenter,boxes(-43,-51,43,51)
+5436 region=relcenter,boxes(-43,-51,43,51)
+5564 region=relcenter,boxes(-43,-50,43,50)
+5692 region=relcenter,boxes(-43,-50,43,50)
+5820 region=relcenter,boxes(-43,-50,43,50)
+5948 region=relcenter,boxes(-42,-50,42,50)
+6076 region=relcenter,boxes(-42,-50,42,50)
+6204 region=relcenter,boxes(-42,-50,42,50)
+6332 region=relcenter,boxes(-42,-50,42,50)
+6460 region=relcenter,boxes(-41,-44,41,44)
+}}}
+
+And we run imframe using dac_repeat.pl like this:
+
+dac_repeat.pl --task imframe --repeat in --repeat-freq rnovalmc_m2_%f.map --repeat out --repeat-freq rnovalmc_m2_small_%f.map --args-file dac_imframe_args.txt
+